1. Field of the Invention
The present invention relates to liquid ejection heads for ejecting liquid and to liquid ejection apparatuses.
2. Description of the Related Art
An ink jet recording head, which is a typical liquid ejection head, is positioned with respect to a guide shaft of an ink jet recording apparatus, which is a liquid ejection apparatus, via a carriage (an attaching portion). The ink jet recording head attached to the carriage is scanned along the guide shaft and ejects ink onto a recording medium, such as paper, to form an image.
At this time, the ink jet recording head ejects ink based on an assumption that the direction in which the ejection ports, through which ink is ejected, are arrayed is exactly perpendicular to the scanning direction of the ink jet recording head. However, if the ink jet recording head or the carriage has variation derived from the manufacturing process, the direction of the ejection port array may be inclined, not perpendicular, to the scanning direction. If the direction of the ejection port array is inclined, liquid fails to land on the target position of the recording medium, which may degrade the image quality.
Accordingly, the ink jet recording head needs to be precisely positioned with respect to the carriage such that the direction of the ejection port array is exactly perpendicular to the scanning direction of the ink jet recording head.
Japanese Patent Laid-Open No. 2010-46853 discloses a structure for positioning an ink jet recording head with respect to a carriage.
FIGS. 6A to 6F are diagrams of a carriage B102 of a main body of an ink jet recording apparatus and an ink jet recording head B1 attached thereto. FIGS. 6G and 6H are diagrams of the carriage B102.
As shown in FIGS. 6A and 6B, the ink jet recording head B1 is attached to the carriage B102, which is scanned along a guide shaft B101 of the main body of the ink jet recording apparatus.
When the ink jet recording head B1 is attached to the carriage B102, the ink jet recording head B1 is subjected to a reaction force A acting in a direction indicated by the arrow (FIG. 6E), which is exerted by plate springs B111 (FIG. 6C) that follow a head set lever provided on the carriage B102. The ink jet recording head B1 is also subjected to a reaction force B acting in a direction indicated by the arrow (FIG. 6F), which is exerted by electric connectors B112 (FIG. 6D) that electrically connect the ink jet recording head B1 and the main body of the ink jet recording apparatus. With these reaction forces A and B, the ink jet recording head B1 is positioned with respect to the carriage B102. By abutting a positioning portion on the ink jet recording head B1 to a positioning portion on the carriage B102 utilizing the reaction forces A and B, positioning of the ink jet recording head B1 in the direction Y, i.e., a conveying direction of a recording medium (FIG. 6B), is achieved, and the ink jet recording head B1 is fixed. More specifically, positioning portions B50a, B50b, and B50d, on the ink jet recording head B1 (FIG. 6F) are abutted to positioning portions B120a, B120b, and B120d (FIGS. 6G and 6H) on the carriage B102, respectively. The positioning portions B50a and B50b on the ink jet recording head B1 are provided on a support substrate B12, the positioning portions B50d and B50e are provided on an ink supply member B21 (housing).
Herein, the positioning portions B50a and B50b provided on the support substrate B12 of the ink jet recording head B1 and used for the positioning in the direction Y also serve as reference surfaces when the support substrate B12 and the recording element substrate B11 (liquid ejection substrate) are bonded. As in this case, by making the positioning portions of the ink jet recording head B1 and carriage B102 also serve as the reference surfaces when the support substrate B12 and the recording element substrate B11 are bonded, the recording element substrate B11 can be precisely positioned with respect to the carriage B102.
However, as shown in FIG. 7E, in the ink jet recording head B1, the support substrate B12 may be fixed to the ink supply member B21 with an inclination in the direction indicated by the arrow.
In this case, two positioning portions (B50d and B50e) on the ink supply member B21 are abutted to the positioning portions on the carriage B102 by the reaction force A. However, although one of the positioning portions provided on the support substrate B12, namely, B50a, is abutted to the positioning portion on the carriage B102 by the reaction force B, the other positioning portion, namely, B50b, may not be abutted to the positioning portion on the carriage B102. This may degrade the positioning accuracy of the ink jet recording head B1 with respect to the carriage B102 in the direction Y, leading to a decrease in image quality.